I'm using a freewing 6 blade 89mm in the identical duct, on 4 cell 4000mah 40c with 96 amps. Could that same 4 cell drive the 7 blade haoye fan? The motor is 110 amp continuous not max, and the ESC is 100, 120 peak.

I feel that a 90mm fan should produce 6 lbs. static. Is that true of the Haoye?

A future project, when I can afford a high-end fan, would come together later. For now, I'd like to put components I already have to use. The same 2800 kv 110 amp inrunner on 6-blade Freewing with 4 cell 40c 4 amphour only produces about 3.5 to 4 lbs. I have an inaccurate measurement. Given. I'll have to find a better static testbed and thrust measure. 2.5 kilos is 5.5 pounds, which is the least I'd expect of even a cheap fan.

Can you provide any tips for balancing the rotor? How the hell is the rotor suspended for balancing?
So far I've been using them as is, and the dynamicly balanced HET 6904 is the best.

Incidently...the current crop of fan motors are for 6 cells. I realize that. They pull less current at the same wattage, as a lower volt pack on a higher KV motor.

I've employed a 3 cell pack to a 4900kv motor on a HET 6904 with excellent results, albeit the ESC is big and hot. Am I wasting power in the HEAT?